1. Field of the Invention
The present invention relates to a method for producing L-glutamic acid by fermentation.
2. Description of the Prior Art
Various L-glutamic acid producing bacterial wild strains are known especially in the genus Brevibacterium or Corynebacterium. In order to increase L-glutamic acid productivity of the known wild strains, artificial mutation is given to the wild strains.
Examples of such artificial mutants are mutants of Brevibacterium resistant to S-2-amino-ethyl-cysteine (Japanese Published Unexamined Patent Application No. 126877/1975), mutants of Brevibacterium and Corynebacterium resistant to fluorocitric acid, ketomalonic acid, .alpha.-amino-.beta.-hydroxyvaleric acid, DL-threoninehydroxamate, 2-amino-3-phosphopropionic acid or 5-aminolevulinic acid (Japanese Published Unexamined Patent Application No. 89045/1979), mutants of Brevibacterium and Corynebacterium sensitive to lysozyme (Japanese Published Unexamined Patent Application No. 122794/1979), mutants of Brevibacterium and Corynebacterium having reduced activity of pyruvic acid dehydrogenase (Japanese Published Unexamined Patent Application No. 21762/1980), mutants resistant to glutamic acid or glutamic acid-analgue of Brevibacterium or Corynebacterium (Japanese Published Unexamined Patent Application No. 21763/1980), and mutants of Brevibacterium resistant to 2,6-pyridine-dicarboxylic acid (Japanese Published Unexamined Patent Application No. 21764/1980).
It has, however, become difficult to increase the yields of L-glutamic acid by the artificial mutation techniques. A need therefore, continues to exist for the development of novel microorganisms capable of producing L-glutamic acid in high yields.